10:00 p.m. update: The threat of showers and thunderstorms is over but with abundant low level moisture and stagnant air, dense fog is expected to develop overnight. Visibilities may be reduced to 1/4 of a mile or less, so use caution.

7:35 p.m. update: A tornado warning has been issued for a storm passing through extreme southern Charles County and into St. Mary's County. This warning continues through 8:30 p.m. Anyone in the area should take cover. This appears to be the last in a series of storms rolling by on the southern periphery of the area.

Through Tonight: We'll stick with a slight risk of showers and storms (some potentially severe) into the evening, but for the most part things are winding down except maybe over south and east parts of the area. The high humidity and warm temperatures of today begin to melt away behind a cold front moving through. Lows reach the mid-50s to near 60.

Tomorrow (Thursday): Thursday is looking like a pretty nice day overall. Mostly sunny skies and temperatures rising into the mid-70s mix with light winds early. By afternoon, west winds should be increasing to about 10-20 mph with higher gusts. Temperatures also likely peak midday or early afternoon before dropping during the later part of the afternoon as much cooler air starts filtering in.

6:00 p.m. update: While the immediate D.C. area was spared from tornadic thunderstorms, locations to our south and southeast have not been as lucky. Tornado warnings were issued in Stafford, southeast Charles and central St. Mary's county earlier this evening. A waterspout was spotted just SW of Avenue, MD in St. Mary's county around 5:30 p.m. Further south, in Caroline County, Md. a tornado was seen on the ground just before 5 p.m. Additional tornadic storms have impacted the Richmond area this evening with at least one reported touchdown.

The worst of the storminess is probably over, but one more round of showers/storms well southwest of Washington may pass through the southeast suburbs in the next couple hours. A tornado watch remains in effect through 8 p.m. in these areas.

4:40 p.m. update: While much of the region has seen the weather calm compared to earlier, some storms have worked their way into the far southern sections of our area this afternoon. In particular, several rotating storms in and south of Stafford County, Va. are looking problematic. A Tornado Warning that was issued for Stafford will continue through 5 p.m. The storm may impact Charles County, Md. after crossing the Potomac River over the next hour. If you are in the path of these storms, take cover now.

3:25 p.m. update: It's been another wild weather day, but perhaps not as wild as it could have been given the Tornado Watch and all. We're seeing a break in the action right now and there is a good chance there won't be much, if anything, else to come through much of the area. Highs generally reached the low-and-mid 70s earlier today and temperatures have fallen back a bit since, though sunshine breaking back out may push them back to earlier values.

Cliff Mass also admits that those pressures are measured when the storms are offshore. That makes sense considering the discussion in the other thread by Bombo and others about storms at sea. However I am still interested in the claim that Ohio still holds the land low pressure record (non-tropical, non-Pacific-NW-buoy-maybe) as stated here http://blog.cleveland.com/metro/2010/10/wind_storm_causes_brief_havoc.html

What made this storm extremely unusual, possibly unique, and tremendously fascinating - at least in my experience - was that intensified completely overland (unlike Cliff's Washington State storms and "not easters") - and did so without any significant feed of Gulf moisture into the center of the storm.

That is, the storm intensified almost exclusively from the exceptional strength of dynamical mechanisms (e.g., unusually intense jet streams, intense lower and upper level fronts) without significant benefit of the thermodynamical influence of the heat released by condensing atmospheirc moisture.

Hey guys, I was trying to comment on the storm situation last night, but kept getting the message that my comment was being held for approval by the "blog owner." Any idea what that means? In order to get this comment to show up, I (@fleeciewool) have been reduced to using someone else's handle, and let's just say I'm not a huge fan of my new name...

Cliff Mass is wrong about the deepest non-tropical lows...his reasoning applies only to the Northern Hemisphere!

The strongest non-tropical lows on earth occur over the "Roaring Forties" and the higher oceanic latitudes of the Southern Hemisphere, where huge land masses don't break up the intense storms which form down there. High westerly winds associated with Southern Hemisphere storms used to wreak havoc with tall ships attempting the westward passage around Cape Horn and through the Straits of Magellan. On occasion during the Age of Sail, ships would round Cape Horn only to be blown back east three or more times before successfully entering the Pacific Ocean. Even today the added fuel cost is a reason why many ships won't round the Cape and instead pass through the Panama Canal. In fact one reason for the construction of the Panama Canal a hundred years ago was the high cost incurred fighting the westerly headwinds near Cape Horn.